The present invention relates to warheads with blast wave conditioners and in particular to devices for quickly removing a door to permit entry through the doorway.
In various applications, particularly in military and law enforcement scenarios, it may be desired to quickly remove a door so as to gain access to a certain doorway which would otherwise be blocked by the presence of a locked door. For example, drug enforcement personnel frequently need to gain rapid entry into a dwelling during a drug raid. The entry must be performed quickly in order to prevent the occupants from hiding or destroying the drugs, from escaping the premises or from seizing arms and violently resisting the efforts of the authorities. Similarly, in various circumstances, police and/or military forces must be able to gain quick access to a house or other structure protected by a door, typically locked, in order to seize, preferably alive, one or more wanted persons inside the premises and/or to free innocent hostages held inside the structure. In all these cases access must be gained in such a way at to avoid injury to both the persons attempting to gain access and the persons located in the structure beyond the door to be removed.
Israel Patent No. 106629 teaches an entry system intended for such applications which is tired from a rifle with a bullet-trap arresting a standard bullet. The warhead has essentially of disk-shape with some curvature. Opening the door is achieved by the action of high pressure detonation products which impinge on its surface and displace it from its frame, without causing more than minimal damage to persons and property near and beyond the door. Further to the device of Israel Patent No. 106629, U.S. Pat. No. 6,408,765 by the same inventors and same assignees teaches a safety connector for the above device in order to eliminate a potential safety hazard, namely the possibility that the tail of the device be propelled rearwards at high velocity by the effect of the explosion, thereby injuring personnel. The safety connector being configured to reduce shock forces acting on the tail resulting from detonation of the explosive charge. This device is illustrated in FIG. 1.
The device as taught by Israel Patent 106629 and U.S. Pat. No. 6,480,765 is effective and safe and has been fielded by the US Army under the name of GREM. There is however a desire to achieve the same effect with a device of smaller dimensions, such as for example compatible with the M203 40 mm grenade launcher. For the specific application of a door breaching grenade of this caliber, the device would preferably satisfy the following conditions:                1. Delivering sufficient pressure impulse to open the door.        2. Avoid breaking through the door in order to minimize fragment and pressure damage to persons within the room.        3. Avoid hazards to gunner that could arise from both from fragments projected from the rear part of the charge or ricochets from the door.        4. Provide sufficient effect versus heavy steel doors without causing excessive damage to light (e.g., wooden) doors.        
A grenade with an essentially unconfined charge will generate a spherical blast wave pattern. As a result, the highest pressure is obtained along the main axis and will result in excessive peak pressure at the impact point. Depending on the type of door, and in particular for thin doors, such peak pressure might generate excessive damage. In order to mitigate such damage, a stand-off device is provided in U.S. Pat. Nos. 8,413,586 and 8,468,946, as illustrated in FIG. 2. Such stand-off extension device involves extra weight and complexity.